/**
 * $RCSfile$
 * $Revision$
 * $Date$
 *
 * Copyright 2003-2007 Jive Software.
 *
 * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.jivesoftware.smackx.packet;

import org.jivesoftware.smack.packet.IQ;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;

/**
 * A Time IQ packet, which is used by XMPP clients to exchange their respective
 * local times. Clients that wish to fully support the entitity time protocol
 * should register a PacketListener for incoming time requests that then respond
 * with the local time. This class can be used to request the time from other
 * clients, such as in the following code snippet:
 * 
 * <pre>
 * // Request the time from a remote user.
 * Time timeRequest = new Time();
 * timeRequest.setType(IQ.Type.GET);
 * timeRequest.setTo(someUser@example.com/resource);
 * 
 * // Create a packet collector to listen for a response.
 * PacketCollector collector = con.createPacketCollector(
 *                new PacketIDFilter(timeRequest.getPacketID()));
 * 
 * con.sendPacket(timeRequest);
 * 
 * // Wait up to 5 seconds for a result.
 * IQ result = (IQ)collector.nextResult(5000);
 * if (result != null && result.getType() == IQ.Type.RESULT) {
 *     Time timeResult = (Time)result;
 *     // Do something with result...
 * }
 * </pre>
 * <p>
 * 
 * Warning: this is an non-standard protocol documented by <a
 * href="http://www.xmpp.org/extensions/xep-0090.html">XEP-0090</a>. Because
 * this is a non-standard protocol, it is subject to change.
 * 
 * @author Matt Tucker
 */
public class Time extends IQ {

	private static SimpleDateFormat utcFormat = new SimpleDateFormat(
			"yyyyMMdd'T'HH:mm:ss");
	private static DateFormat displayFormat = DateFormat.getDateTimeInstance();

	private String utc = null;
	private String tz = null;
	private String display = null;

	/**
	 * Creates a new Time instance with empty values for all fields.
	 */
	public Time() {

	}

	/**
	 * Creates a new Time instance using the specified calendar instance as the
	 * time value to send.
	 * 
	 * @param cal
	 *            the time value.
	 */
	public Time(Calendar cal) {
		TimeZone timeZone = cal.getTimeZone();
		tz = cal.getTimeZone().getID();
		display = displayFormat.format(cal.getTime());
		// Convert local time to the UTC time.
		utc = utcFormat.format(new Date(cal.getTimeInMillis()
				- timeZone.getOffset(cal.getTimeInMillis())));
	}

	/**
	 * Returns the local time or <tt>null</tt> if the time hasn't been set.
	 * 
	 * @return the lcocal time.
	 */
	public Date getTime() {
		if (utc == null) {
			return null;
		}
		Date date = null;
		try {
			Calendar cal = Calendar.getInstance();
			// Convert the UTC time to local time.
			cal.setTime(new Date(utcFormat.parse(utc).getTime()
					+ cal.getTimeZone().getOffset(cal.getTimeInMillis())));
			date = cal.getTime();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return date;
	}

	/**
	 * Sets the time using the local time.
	 * 
	 * @param time
	 *            the current local time.
	 */
	public void setTime(Date time) {
		// Convert local time to UTC time.
		utc = utcFormat.format(new Date(time.getTime()
				- TimeZone.getDefault().getOffset(time.getTime())));
	}

	/**
	 * Returns the time as a UTC formatted String using the format
	 * CCYYMMDDThh:mm:ss.
	 * 
	 * @return the time as a UTC formatted String.
	 */
	public String getUtc() {
		return utc;
	}

	/**
	 * Sets the time using UTC formatted String in the format CCYYMMDDThh:mm:ss.
	 * 
	 * @param utc
	 *            the time using a formatted String.
	 */
	public void setUtc(String utc) {
		this.utc = utc;

	}

	/**
	 * Returns the time zone.
	 * 
	 * @return the time zone.
	 */
	public String getTz() {
		return tz;
	}

	/**
	 * Sets the time zone.
	 * 
	 * @param tz
	 *            the time zone.
	 */
	public void setTz(String tz) {
		this.tz = tz;
	}

	/**
	 * Returns the local (non-utc) time in human-friendly format.
	 * 
	 * @return the local time in human-friendly format.
	 */
	public String getDisplay() {
		return display;
	}

	/**
	 * Sets the local time in human-friendly format.
	 * 
	 * @param display
	 *            the local time in human-friendly format.
	 */
	public void setDisplay(String display) {
		this.display = display;
	}

	public String getChildElementXML() {
		StringBuilder buf = new StringBuilder();
		buf.append("<query xmlns=\"jabber:iq:time\">");
		if (utc != null) {
			buf.append("<utc>").append(utc).append("</utc>");
		}
		if (tz != null) {
			buf.append("<tz>").append(tz).append("</tz>");
		}
		if (display != null) {
			buf.append("<display>").append(display).append("</display>");
		}
		buf.append("</query>");
		return buf.toString();
	}
}